Pen state detection circuit, method, and device, and parameter supply device

ABSTRACT

A pen state detection circuit is incorporated in electronic equipment having a touch sensor of a capacitive system made of planarly disposed multiple sensor electrodes. The pen state detection circuit is configured to perform acquiring, from the touch sensor, signal distribution indicating a change in capacitance associated with approach of a pen-side electrode included in an electronic pen, and estimating a state of the electronic pen according to an input-output model. In the input-output model features relating to the acquired signal distribution are input and a state quantity of the electronic pen is output. The pen state detection circuit is configured to be capable of setting an input-output model that is different depending on a change in an outer shape of the electronic pen or the electronic equipment.

BACKGROUND Technical Field The present disclosure relates to a pen statedetection circuit, a pen state detection method, and a pen statedetection device, as well as a parameter supply device. Description ofthe Related Art

A writing input system made as a combination of an electronic pen andelectronic equipment is known. In this kind of system, it is desirablethat an indicated position of the electronic pen be detected by theelectronic equipment with high accuracy. For example, in PCT PatentPublication WO2019/013222 (hereinafter, Patent Document 1), a method isdisclosed in which an indicated position of an electronic pen istentatively detected, a position calibration value corresponding to theindicated position is obtained, and the indicated position is correctedaccording to the position calibration value. More specifically, it isdescribed that a detection value corresponding to an ideal value of theindicated position is obtained by having a user's electronic pen trace atest pattern rendered on a display panel.

As the writing input system is repeatedly used, the outer shape of theelectronic pen or of the electronic equipment may be deformed sometimes.Similarly, as this system is continuously used, the combination of theelectronic pen and the electronic equipment or the like may change.Accordingly, the geometric relation between a pen-side electrodeincluded in the electronic pen and a sensor electrode incorporated inthe electronic equipment may change, which in turn causes the shapepattern tendency of signal distribution indicative of capacitance changeto vary.

For example, in the case of defining one input-output model by use ofthe correction method disclosed in Patent Document 1 and thereafterestimating the state of the electronic pen from signal distributionaccording to such definitive input-output model, it is possible that thepen state detection accuracy may decrease due to the above-describedchanges in the outer shape of the pen or the equipment or thecombination between a particular pen and equipment. Thus, in the methoddisclosed in Patent Document 1, a need exists for improvement so as tomaintain the detection accuracy.

BRIEF SUMMARY

The present disclosure is made in view of the above-described technicalproblem, and according to one aspect is directed to providing a penstate detection circuit, a pen state detection method, and a pen statedetection device, as well as a parameter supply device that can maintainthe pen state detection accuracy irrespective of the use condition of anelectronic pen or electronic equipment.

A pen state detection circuit according to a first aspect of the presentdisclosure is a circuit incorporated in electronic equipment, theelectronic equipment having a touch sensor of a capacitive system madeof planarly disposed multiple sensor electrodes. The pen state detectioncircuit performs acquiring, from the touch sensor, signal distributionindicating a change in capacitance associated with approach of apen-side electrode included in an electronic pen, and estimating a stateof the electronic pen according to an input-output model in whichfeatures relating to the acquired signal distribution are input and astate quantity of the electronic pen is output. The pen state detectioncircuit is configured to be capable of setting an input-output modelthat is different depending on a change in an outer shape of theelectronic pen or the electronic equipment.

A pen state detection method according to a second aspect of the presentdisclosure is a method carried out with use of a pen state detectioncircuit incorporated in electronic equipment, the electronic equipmenthaving a touch sensor of a capacitive system made of planarly disposedmultiple sensor electrodes. The pen state detection method includesacquiring, from the touch sensor, signal distribution indicating achange in capacitance associated with approach of a pen-side electrodeincluded in an electronic pen, and estimating a state of the electronicpen in accordance with an input-output model in which features relatingto the acquired signal distribution are input and a state quantity ofthe electronic pen is output. An input-output model that is setdifferently depending on a change in an outer shape of the electronicpen or the electronic equipment.

A pen state detection device according to a third aspect of the presentdisclosure includes the above-described pen state detection circuit, aninformation acquiring section that acquires model selection informationrelating to the outer shape of the electronic pen or the electronicequipment, and a parameter setting section that sets, in the pen statedetection circuit, model parameters that allow identification of theinput-output model corresponding to the model selection informationacquired by the information acquiring section.

A parameter supply device according to a fourth aspect of the presentdisclosure is a device configured to be capable of mutuallycommunicating with a pen state detection device. The pen state detectiondevice includes the above-described pen state detection circuit, aninformation acquiring section that acquires model selection informationrelating to the outer shape of the electronic pen or the electronicequipment, and a parameter setting section that sets, in the pen statedetection circuit, model parameters that allow identification of theinput-output model selected according to the model selection informationacquired by the information acquiring section. The parameter supplydevice includes a storage section that stores the model parameters insuch a manner as to associate the model parameters with the modelselection information, and a control section that, when receiving themodel selection information from the pen state detection device, carriesout control of reading out the model parameters corresponding to themodel selection information from the storage section and transmittingthe model parameters to the pen state detection device.

A pen state detection circuit according to a fifth aspect of the presentdisclosure is a circuit incorporated in electronic equipment having atouch sensor of a capacitive system made of planarly disposed multiplesensor electrodes. The pen state detection circuit performs acquiring,from the touch sensor, signal distribution indicating a change incapacitance associated with approach of a pen-side electrode included inan electronic pen, and estimating a state of the electronic penaccording to an input-output model in which features relating to theacquired signal distribution are input and a state quantity of theelectronic pen is output. The pen state detection circuit is configuredto be capable of setting an input-output model that is differentdepending on a combination of two or more of a type of the electronicpen, a type the electronic equipment, a type of the touch sensor, and auser.

A pen state detection method according to a sixth aspect of the presentdisclosure is a method carried out with use of a pen state detectioncircuit incorporated in electronic equipment, the electronic equipmenthaving a touch sensor of a capacitive system made of planarly disposedmultiple sensor electrodes. The pen state detection method includesacquiring, from the touch sensor, signal distribution indicating achange in capacitance associated with approach of a pen-side electrodeincluded in an electronic pen, and estimating a state of the electronicpen according to an input-output model in which features relating to theacquired signal distribution are input and a state quantity of theelectronic pen is output. An input-output model is set differentlydepending on a combination of two or more of a type of the electronicpen, a type of the electronic equipment, a type of the touch sensor, anda user.

A pen state detection device according to a seventh aspect of thepresent disclosure includes the above-described pen state detectioncircuit, an information acquiring section that acquires model selectioninformation relating to the combination of two or more of the types ofthe electronic pen, the electronic equipment, and the touch sensor, andthe user, and a parameter setting section that sets, in the pen statedetection circuit, model parameters that allow identification of theinput-output model corresponding to the model selection informationacquired by the information acquiring section.

A parameter supply device according to an eighth aspect of the presentdisclosure is a device configured to be capable of mutuallycommunicating with a pen state detection device. The pen state detectiondevice includes the above-described pen state detection circuit, aninformation acquiring section that acquires model selection informationrelating to the combination of two or more of a type of the electronicpen, a type of the electronic equipment, a type of the touch sensor, andthe user, and a parameter setting section that sets, in the pen statedetection circuit, model parameters that allow identification of theinput-output model corresponding to the model selection informationacquired by the information acquiring section. The parameter supplydevice includes a storage section that stores the model parameters insuch a manner as to associate the model parameters with the modelselection information, and a control section that, when receiving themodel selection information from the pen state detection device, carriesout control of reading out the model parameters corresponding to themodel selection information from the storage section and transmittingthe model parameters to the pen state detection device.

According to the present disclosure, it becomes possible to maintain thepen state detection accuracy irrespective of the use condition of theelectronic pen or the electronic equipment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an overall configuration diagram of an input system in whichelectronic equipment as a pen state detection device in one embodimentof the present disclosure is incorporated;

FIG. 2 is a block diagram illustrating one example of the configurationof the electronic equipment of FIG. 1;

FIG. 3 is a sequence diagram relating to operation of the input systemillustrated in FIG. 1;

FIG. 4 is a schematic diagram partially illustrating an electronic penof FIG. 1;

FIG. 5A is a diagram illustrating one example of first signaldistribution detected from a touch sensor when the electronic pen is ina contact state;

FIG. 5B is a diagram illustrating one example of second signaldistribution detected from the touch sensor when the electronic pen isin the contact state;

FIG. 6 is a diagram illustrating tendency of an estimation errorrelating to an indicated position;

FIG. 7 is a schematic configuration diagram illustrating one example ofan input-output model implemented by a touch integrated circuit (IC) ofFIG. 2;

FIG. 8A is a schematic sectional view illustrating the state in which atouch surface of the electronic equipment curves in an upwardlyprotruding shape;

FIG. 8B is a diagram illustrating a change in signal distributionbetween before and after the curving of the touch surface;

FIG. 9 is a diagram illustrating one example of a data structure of afirst table of a parameter database (DB);

FIG. 10A is a schematic sectional view illustrating the state in which aprotective film is stuck to the touch surface of the electronicequipment;

FIG. 10B is a diagram illustrating a change in signal distributionbetween before and after the sticking of the protective film;

FIG. 11 is a diagram illustrating one example of a data structure of asecond table of the parameter DB;

FIG. 12A is a schematic side view illustrating the state in which a tipelectrode of the electronic pen has been worn out;

FIG. 12B is a diagram illustrating a change in signal distributionbetween before and after the wearing-out of the tip electrode;

FIG. 13 is a diagram illustrating one example of a data structure of athird table of the parameter DB;

FIG. 14 is a diagram illustrating one example of a data structure of afourth table of the parameter DB;

FIG. 15 is a diagram illustrating one example of a data structure of afifth table of the parameter DB;

FIG. 16 is an overall configuration diagram of an input system in afirst modification example; and

FIG. 17 is a block diagram illustrating one example of the configurationof electronic equipment in a second modification example.

DETAILED DESCRIPTION Configuration of Input System 10 OverallConfiguration

FIG. 1 is an overall configuration diagram of an input system 10 inwhich electronic equipment 12 is incorporated as a pen state detectiondevice in one embodiment of the present disclosure. The input system 10is configured to be capable of generating a digital ink (or ink data)with high reproducibility with respect to writing input made with use ofan electronic pen 14. As the data format of the digital ink, orso-called “ink description language,” Wacom Ink Layer Language (WILL)™,Ink Markup Language (InkML), or Ink Serialized Format (ISF) may be used.

Specifically, the input system 10 includes at least one unit ofelectronic equipment 12, at least one electronic pen 14, and a serverdevice 16 (corresponding to a “parameter supply device”). Each unit ofelectronic equipment 12 can mutually communicate with the server device16 through a network NT.

The electronic equipment 12 is a general-purpose electronic device or adedicated electronic device including a touch panel display 32 (FIG. 2).Examples of the general-purpose electronic device include a tablet-typeterminal, a smartphone, a personal computer, and so forth. Examples ofthe dedicated electronic device include a digital signage device (aso-called electronic billboard), a wearable terminal, and so forth.

The electronic pen 14 is a pen-type pointing device and is configured tobe capable of communicating with the electronic equipment 12unidirectionally or bidirectionally through capacitive coupling formedbetween the electronic pen 14 and the electronic equipment 12. The usercan draw pictures or write characters on the electronic equipment 12 byholding the electronic pen 14 and moving the electronic pen 14 whilepressing the pen tip against a defined touch surface. The electronic pen14 is a stylus based on the active capacitive coupling system (AES) orthe electromagnetic induction system (EMR), for example.

The server device 16 is a computer that carries out overall controlrelating to supply of model parameters 20 and may be of either a cloudtype or an on-premise type. Here, the server device 16 isdiagrammatically represented as a single computer. However, instead, theserver device 16 may be formed by a computer group constituting adistributed system. The server device 16 is configured to include aserver-side communication section 22, a server-side control section 24,and a server-side storage section 26.

The server-side communication section 22 is an interface that transmitsand receives electric signals to and from an external device. Thisallows the server device 16 to receive model selection information 18from the electronic equipment 12 and transmit the model parameters 20 tothe electronic equipment 12.

The server-side control section 24 includes an arithmetic processingunit including a central processing unit (CPU) and a graphics processingunit (GPU). The server-side control section 24 functions as a modelselecting section 28, to be described in detail later, by reading out aprogram stored in the server-side storage section 26 and executing theprogram.

The server-side storage section 26 includes a non-transitory,computer-readable storage medium, for example, a hard disk drive (HDD)or a solid state drive (SSD). A database (hereinafter, parameter DB 30)relating to the model parameters 20 is constructed in the server-sidestorage section 26.

FIG. 2 is a block diagram illustrating one example of the configurationof the electronic equipment 12 of FIG. 1. Specifically, the electronicequipment 12 includes a touch panel display 32, a display drive IC 34, atouch IC 36 (corresponding to a “pen state detection circuit”), acommunication module 38, a host processor 40, and a memory 42.

The touch panel display 32 includes a display panel 44 that can displaycontent in a visible manner, and a planar touch sensor 46 disposed tooverlap with the display panel 44 in plan view. In the illustratedexample, the touch sensor 46 is a sensor of an “external type” attachedto the display panel 44 from the outside. However, instead, the touchsensor 46 may be a sensor of a “built-in type” (according to furtherclassification, an on-cell type or in-cell type) configured integrallywith the display panel 44.

The display panel 44 can display a monochrome image or a color image,and includes, for example, a liquid crystal panel, an organicelectro-luminescence (EL) panel, or an electronic paper. The displaypanel 44 can have flexibility, to allow the user to perform inputoperation by handwriting on the touch surface of the electronicequipment 12 that is kept at a curved or bent state.

The touch sensor 46 is a sensor of the capacitive system made ofplanarly disposed multiple sensor electrodes. Specifically, the touchsensor 46 includes multiple X line electrodes 47 (see FIG. 10A) fordetecting the position on an X-axis of a sensor coordinate system andmultiple Y line electrodes 48 (see FIG. 10A) for detecting the positionon a Y-axis of the sensor coordinate system. In this case, the X lineelectrodes 47 are provided to extend along the Y-axis direction and aredisposed at equal intervals in the X-axis direction. The Y lineelectrodes 48 are provided to extend along the X-axis direction and aredisposed at equal intervals in the Y-axis direction. The touch sensor 46may be, instead of the above-described sensor of the mutual capacitancesystem, a sensor of the self-capacitance system in which block-shapedelectrodes are disposed in a two-dimensional matrix.

The display drive IC 34 is an integrated circuit that is electricallyconnected to the display panel 44 and that carries out driving controlof the display panel 44. The display drive IC 34 drives the displaypanel 44 according to a display signal supplied from the host processor40. As a result, content indicated by digital ink 58 is displayed on thedisplay panel 44.

The touch IC 36 is an integrated circuit that is electrically connectedto the touch sensor 46 and that carries out driving control of the touchsensor 46. The touch IC 36 drives the touch sensor 46 according to acontrol signal supplied from the host processor 40. Accordingly, thetouch IC 36 carries out a “pen detection function” of detecting thestate of the electronic pen 14 and a “touch detection function” ofdetecting a touch by a finger or the like of the user.

The pen detection function includes a function to scan the touch sensor46, a function to receive and analyze a downlink signal, a function toestimate the state of the electronic pen 14 (for example, a position, anorientation, or a writing pressure of the electronic pen 14), and afunction to generate and transmit an uplink signal including a commandto the electronic pen 14, for example. The touch detection functionincludes a function to two-dimensionally scan the touch sensor 46, afunction to acquire a detection map on the touch sensor 46, and afunction to classify a region on the detection map (for example,classification of a finger, a palm, and so forth), for example.

A graphical user interface (GUI) is constructed by combining the inputfunction provided by the electronic pen 14 and the touch sensor 46 andthe output function provided by the display panel 44 as described above.

The communication module 38 has a communication function of carrying outwired communication or wireless communication with an external device.This allows the electronic equipment 12 to transmit the model selectioninformation 18 to the server device 16 and receive the model parameters20 from the server device 16.

The host processor 40 includes an arithmetic processing unit including aCPU, GPU, or a micro-processing unit (MPU). The host processor 40functions as an information acquiring section 50, a parameter settingsection 52, an ink generating section 54, and a rendering processingsection 56 by reading out a program stored in the memory 42 andexecuting the program.

The memory 42 includes a non-transitory, computer-readable storagemedium. Here, the computer-readable storage medium is a storing deviceincluding an HDD or a portable medium such as a magneto-optical disc, aread only memory (ROM), a compact disc ROM (CD-ROM), or a flash memory.In the illustrated example, the model selection information 18, themodel parameters 20, and the digital ink 58 are stored in the memory 42.

Operation of Input System 10

The input system 10 in which the electronic equipment 12 is incorporatedas the pen state detection device is configured as described above.Next, description will be made of operation of the input system 10,specifically, cooperative operation of the electronic equipment 12, theelectronic pen 14, and the server device 16, with reference to asequence diagram of FIG. 3. Steps S1 and S9 in this sequence diagram arecarried out by cooperation of the electronic pen 14 and the electronicequipment 12. Steps S4 to S6 are carried out by the server device 16.Meanwhile, the remaining steps are carried out by the electronicequipment 12.

In step S1 in FIG. 3, the host processor 40 of the electronic equipment12 detects the electronic pen 14 used by a user to input writing.Specifically, the electronic equipment 12 attempts pairing with theelectronic pen 14 that is present nearby and detects the electronic pen14 through successful pairing. Alternatively, the electronic equipment12 may detect the electronic pen 14 by receiving user input operation ofinformation relating to the electronic pen 14.

In step S2, the information acquiring section 50 of the electronicequipment 12 acquires the model selection information 18 from theelectronic pen 14 and/or from the electronic equipment 12 itself. Themodel selection information 18 is information necessary for selecting aninput-output model 70 to be described later. Specifically, the modelselection information 18 is [1] information relating to the outer shapeof the electronic pen 14 or the electronic equipment 12 or [2]information relating to a combination of two or more of a type of theelectronic pen 14, a type of the electronic equipment 12, a type of thetouch sensor 46, and the user.

In step S3, the electronic equipment 12 transmits data including themodel selection information 18 acquired in step S2 to the server device16 in the state in which the data is associated with identificationinformation of the electronic equipment 12 (i.e., equipmentidentification (ID)).

In step S4, the server device 16 acquires the model selectioninformation 18 through reception of the data from the electronicequipment 12.

In step S5, the server-side control section 24 (more specifically, themodel selecting section 28) uses the model selection information 18acquired in step S4, as a search key, and refers to the parameter DB 30constructed in the server-side storage section 26. As a result, one setof the model parameters 20 that allows identification of theinput-output model 70 corresponding to the model selection information18 in multiple sets of the model parameters 20 is selected.

In step S6, the server device 16 transmits data including the modelparameters 20 selected in step S5 to the electronic equipment 12 havingthe equipment ID associated with the relevant model selectioninformation 18.

In step S7, the electronic equipment 12 acquires the model parameters 20through reception of data from the server device 16. The modelparameters 20 are stored in the memory 42 of the electronic equipment12.

In step S8, the host processor 40 (more specifically, the parametersetting section 52) carries out setting the model parameters 20 acquiredin step S7, in such a form that the touch IC 36 can use the modelparameters 20. For example, the host processor 40 writes each of therespective values of the model parameters 20 to a corresponding memoryor a corresponding storage area of a register.

In step S9, the electronic equipment 12 carries out desired writingoperation in cooperation with the electronic pen 14. Specifically, theink generating section 54 generates the digital ink 58 made throughassociation of stroke data indicating the trace of the indicatedposition of the electronic pen 14 with meta-information relating to thestroke data. The meta-information includes, for example, documentmetadata, semantic data, device data, categorization data, context data,and so forth.

The rendering processing section 56 analyzes the digital ink 58 read outfrom the memory 42 and executes desired rasterization processing for thestroke data to generate a display signal indicating content of therendering target. The display drive IC 34 drives the display panel 44according to the display signal supplied from the host processor 40. Asa result visualized content is displayed on the display panel 44.

Detection Operation of Pen State

In this manner, the sequence operation illustrated in FIG. 3 ends. Next,the pen state detection operation by the touch IC 36 will be describedwith reference to FIG. 4 to FIG. 7.

One Example of Input Value and Output Value

FIG. 4 is a schematic diagram partially illustrating the electronic pen14 of FIG. 1. At the tip of the electronic pen 14, a tip electrode 60having a substantially conical shape and an upper electrode 62 having abottomless truncated conical shape are coaxially disposed. The tipelectrode 60 and the upper electrode 62 are each a pen-side electrodefor outputting a signal generated by an oscillating circuit 64 (aso-called downlink signal). The oscillating circuit 64 changes theoscillation frequency or switches the transmission destination in atime-division manner. This allows the electronic pen 14 to output twokinds of downlink signals through the tip electrode 60 and the upperelectrode 62.

The touch IC 36 (FIG. 2) of the electronic equipment 12 acquires, fromthe multiple X line electrodes 47, signal distribution indicating achange in the capacitance (more specifically, mutual capacitance orself-capacitance) associated with approach of the tip electrode 60(hereinafter, first signal distribution). Typically, the first signaldistribution has a shape having one peak at a position Q1. Here, theposition Q1 corresponds to the position obtained by projecting the toppart of the tip electrode 60 (position P1) onto the sensor plane.

Similarly, the touch IC 36 acquires signal distribution indicating achange in the capacitance associated with approach of the upperelectrode 62 (hereinafter, second signal distribution) from the multipleX line electrodes 47. Typically, the second signal distribution has ashape having one peak or two peaks at a position Q2. Here, the positionQ2 corresponds to the position obtained by projecting the shoulder part(position P2) of the upper electrode 62 onto the sensor plane.Furthermore, a position Q3 to be described later corresponds to theposition obtained by projecting the center (position P3) of the uppersurface of the truncated conical shape of the upper electrode 62 ontothe sensor plane.

FIG. 5A and FIG. 5B are diagrams each illustrating one example of signaldistribution detected from the touch sensor 46 at the time when theelectronic pen 14 is in the contact state. Specifically, FIG. 5Aillustrates the first signal distribution, and FIG. 5B illustrates thesecond signal distribution. The abscissa axis of the graph indicates therelative position (unit: mm) with respect to the indicated position ofthe electronic pen 14. The ordinate axis of the graph indicates a signalvalue (unit: none) normalized to [0, 1]. Regarding this signal value,the positive and negative signs are defined in such a manner that thesignal value becomes “positive” when the electronic pen 14 approaches.The shape of each of the first signal distribution and the second signaldistribution changes according to the inclination angle of theelectronic pen 14. In the present diagrams, three curves each obtainedwith a change in the inclination angle are represented in an overlappedmanner.

As illustrated in FIG. 5A, the first signal distribution has asubstantially similar shape irrespective of the magnitude of theinclination angle. This is because, while the electronic pen 14 is used,normally the top part of the tip electrode 60 is present at the positionclosest to the sensor plane and the position Q1 substantiallycorresponds with the position P1. On the other hand, as illustrated inFIG. 5B, in the second signal distribution, the position or the numberof peaks largely changes according to a change in the inclination angle.This is because, while the electronic pen 14 is used, normally, anyplace on the shoulder part of the upper electrode 62 is present at theposition closest to the sensor plane, and the distance between thepositions Q1 and Q2 changes according to the inclination angle.

The position and orientation of the electronic pen 14 (hereinafterreferred to also as a pen state) can be estimated by using thecoordinates of these positions Q1 and Q2. For example, the indicatedposition is equivalent to the position Q1 illustrated in FIG. 4.Moreover, the inclination angle is equivalent to an angle θ formed bythe sensor plane and the axis of the electronic pen 14. That is, θ=0°holds in the state in which the electronic pen 14 is horizontal to thesensor plane, and θ=90° holds in the state in which the electronic pen14 is perpendicular to the sensor plane. As the physical quantityindicating the tilt state of the electronic pen 14, instead of theabove-described angle, the orientation may be used, for example.

FIG. 6 is a diagram illustrating the tendency of an estimation errorrelating to the indicated position. The abscissa axis of the graphindicates the actual value (unit: mm) of the indicated position and theordinate axis of the graph indicates the estimated value (unit: mm) ofthe indicated position. Here, the midpoint of the X line electrode 47 inthe width direction is defined as X=0 (mm). When the estimation error is0, a straight line is obtained that passes through an origin O and has aslope of 1.

For example, because the signal distribution is a collection of signalvalues sampled at equal intervals (pitch ΔX), interpolation calculationis carried out in order to estimate the peak of the signal distribution(i.e., indicated position) more accurately. However, a fitting erroroccurs depending on the kind of interpolation function, and an“interpolation approximation error” may occur that is periodic in unitsof pitch.

In the case of estimating the inclination angle in reference to theposition P3 (see FIG. 4) on the upper electrode 62, the position Q2corresponds with the position Q3 in the case of θ=0°, and hence, anestimation error attributable to the inclination angle does not occur.However, in the case of θ>0°, the inclination angle is estimated to besmall due to the gap between the positions Q2 and Q3. As a result, theobtained estimated value shifts in the positive direction (i.e., theinclination direction of the electronic pen 14), and a so-called “offseterror” occurs.

As described above, when the pen state is estimated by use of the twopen-side electrodes different from each other in position and shape, theestimation accuracy of the indicated position or the inclination anglevaries due to the above-described interpolation approximation error orthe offset error. By introducing the following input-output model 70,these two kinds of errors can simultaneously be reduced, so as toimprove the pen state estimation accuracy.

Configuration Example of Input-output Model 70

FIG. 7 is a schematic configuration diagram illustrating one example ofthe input-output model 70 implemented by the touch IC 36 of FIG. 2. Theinput-output model 70 is a model in which features relating to thesignal distribution are input and the state quantity of the electronicpen 14 is output. Specifically, the input-output model 70 is a neuralnetwork formed by sequentially connecting a front-stage calculatingsection 72, a back-stage calculating section 74, and an adder 76 inseries. The network structure is not limited to the example of thepresent diagram, and various configurations may be employed.

The front-stage calculating section 72 functions as a first estimatingsection that estimates the inclination angle of the electronic pen 14.The back-stage calculating section 74 and the adder 76 function as asecond estimating section that estimates the indicated position of theelectronic pen 14. Circle marks in the drawing denote calculation unitsequivalent to neurons of the neural network. In the calculation units of“T,” the respective values of a “first local feature” corresponding tothe tip electrode 60 are stored. In the calculation units of “U,” therespective values of a “second local feature” corresponding to the upperelectrode 62 are stored. The “inclination angle” is stored in thecalculation unit of “A.” The “relative position” is stored in thecalculation unit of “P.”

The front-stage calculating section 72 is a hierarchical neural netcalculating section including an input layer 72 i, a middle layer 72 m,and an output layer 72 o, for example. The input layer 72 i includes Ncalculation units for inputting the respective values of the secondlocal feature. The middle layer 72 m includes M (here, M=N) calculationunits. The output layer 72 o includes one calculation unit foroutputting the inclination angle. Here, the second local feature is afeature indicating shape characteristics of a part of the second signaldistribution including the peak (referred to also as “second localdistribution”). For example, this second local feature may be the slopeof the second local distribution or the absolute value of the slope ormay be the second local distribution itself.

The back-stage calculating section 74 is a hierarchical neural netcalculating section including an input layer 74 i, a middle layer 74 m,and an output layer 74 o, for example. The input layer 74 i includes(N+1) calculation units for inputting the respective values of the firstlocal feature and the inclination angle. The middle layer 74 m includesM (here, M=N) calculation units, for example. The output layer 74 oincludes one calculation unit for outputting the relative positionbetween the reference position and the indicated position. Here, thefirst local feature is a feature indicating shape characteristics of apart of the first signal distribution including the peak (referred toalso as “first local distribution”). For example, this first localfeature may be the slope of the first local distribution or the absolutevalue of the slope or may be the first local distribution itself.

The adder 76 outputs the indicated position of the electronic pen 14 byadding the relative position output from the back-stage calculatingsection 74 to the position of the reference point of the first localdistribution in the sensor coordinate system (i.e., the referenceposition). For example, this reference position may be any of the risingposition, the falling position, or the peak position of the first localdistribution, or a neighboring position thereof. The indicated positionis a position corresponding to the peak center of the first localdistribution and has a higher resolution than the pitch of the X lineelectrodes 47 (or the Y line electrodes 48).

The calculation rule of the input-output model 70 is defined dependingon the respective values of the model parameters 20. For example, themodel parameters 20 include “variable parameters” and “fixedparameters.” The variable parameters include a coefficient thatdescribes an activation function of the calculation unit, or theconnection strength between calculation units. The fixed parameters (orso-called hyperparameters) identify the architecture of a learningmodel. Examples of the hyperparameters include the number of calculationunits that configure each layer, or the number of middle layers. Forexample, when the architecture is fixed, the model parameters 20 mayinclude only the variable parameters.

The model parameters 20 are determined through “supervised learning”with use of training data obtained by actual measurement or computersimulation. For example, in the case of the “actual measurement,” thetraining data is created by random selection of multiple positions onthe sensor plane and measurement of the signal distribution at eachposition. In the case of the “computer simulation,” the training data iscreated by use of physics simulation including electromagnetic fieldanalysis or electrical circuit analysis, or mathematical simulationincluding sampling processing, interpolation processing, or noiseaddition.

Then, the touch IC 36 supplies data including the indicated position andthe inclination angle estimated according to the input-output model 70to the host processor 40. For example, the touch IC 36 may repeatone-dimensional model calculation twice and estimate each of an X-axiscoordinate value and a Y-axis coordinate value and supply the coordinatevalues (X, Y) of the indicated position to the host processor 40.Alternatively, the touch IC 36 may carry out two-dimensional modelcalculation one time, to simultaneously estimate the coordinate values(X, Y) of the indicated position, and supply the coordinate values (X,Y) to the host processor 40.

Selection of Model Parameters 20

As the input system 10 is repeatedly used, the outer shape of theelectronic pen 14 or the electronic equipment 12 may be deformedsometimes. This “change in the outer shape (or change in terms of theouter shape)” means that the shape viewed from the outside (so-calledappearance) physically changes. Alternatively, the “change in terms ofthe outer shape” refers to deformation accompanied by a dynamic changein the electrical or magnetic coupling state of the interface betweenthe electronic pen 14 and the electronic equipment 12 that changesdepending on the time (use condition over time), despite that the sameproduct, pen tip type, or sensor electrode product are staticallyindicated by the same information. That is, the change in the outershape may be either [1] a reversible change including curving andbending or [2] an irreversible change including partial wear orreplacement, or integration or removal of another component.

Similarly, as the input system 10 is repeatedly used, the combination ofthe electronic pen 14 and the electronic equipment 12 may change.Accordingly, the geometric relation between the pen-side electrodeincluded in the electronic pen 14 and the sensor electrode incorporatedin the electronic equipment 12 is changed, which in turn causes theshape pattern tendency of signal distribution indicative of capacitancechange to vary. As a result, if the input-output model 70 is fixedlyimplemented, it may become difficult to sufficiently ensure the penstate detection accuracy.

As such, the server device 16 holds multiple sets of the modelparameters 20 different in the input-output characteristics, and selectsand supplies one set of the model parameters 20 suitable for the usecondition of the electronic pen 14 or the electronic equipment 12.Selection operation of the model selecting section 28 in step S5 in FIG.3 will be described below with reference to FIG. 8A to FIG. 15.

FIRST EXAMPLE

FIG. 8A is a schematic sectional view illustrating the state in whichthe touch surface of the electronic equipment 12 curves into an upwardlyprotruding shape. In the example of the present diagram, the state inwhich the X line electrodes 47, the Y line electrode 48, and a surfacecover 80 are stacked from the lower side to the upper side isillustrated. When the electronic pen 14 approaches the touch surface ofthe electronic equipment 12, capacitive coupling is formed between thetip electrode 60 and each of three X line electrodes 47 present atpositions relatively close to the tip electrode 60. Suppose that, in thefollowing description, the capacitances at the center, on the left side,and on the right side of the drawing are C1, C2, and C3, respectively.As is understood from the present diagram, the geometric positionalrelation between the tip electrode 60 and the X line electrodes 47changes depending on whether or not the electronic equipment 12 iscurved and the curvature thereof. Correspondingly, the relativemagnitude relation among the capacitances C1, C2, and C3 changes.

FIG. 8B is a diagram illustrating change in signal distribution betweenbefore and after the curving of the touch surface. The abscissa axis ofthe graph indicates the position (unit: mm) in the X-axis direction, andthe ordinate axis of the graph indicates the signal value (unit: none).As is understood from the present diagram, the signal distribution of“in curving” (when curved) has such a tendency that the width becomesnarrower and the peak becomes higher compared with the case of “inflat.” Thus, in consideration of such a difference in the distributionshape, multiple sets of the model parameters 20 suitable for the case inwhich the touch surface of the electronic equipment 12 is flat or thecase in which the touch surface is curved or bent are prepared.

FIG. 9 is a diagram illustrating a first example of a data structure ofthe parameter DB 30 of FIG. 1. A first table of the parameter DB 30 isdata of a table format indicating the correspondence relation between“pen type” indicating the type of the electronic pen 14, “sensor curvingdegree” indicating the degree of curving of the touch sensor 46, and“parameter set name” indicating the set name of the model parameters 20.The “pen type” is classified according to the product name, modelnumber, production lot, manufacturer, or the like, of the electronic pen14. The “sensor curving degree” may be qualitatively classified as“absent,” “present,” “low,” “high,” and so forth, or may bequantitatively classified according to the curvature, the bending angle,or the like.

In this case, the information acquiring section 50 of the electronicequipment 12 acquires each of the pen type and the sensor curving degreeas the model selection information 18 (step S2 in FIG. 3). The pen typemay be type information included in a downlink signal from theelectronic pen 14 or may be type information input through operation ofthe electronic equipment 12 by the user. Moreover, the sensor curvingdegree may be a detection value by a strain sensor (not illustrated)disposed in the touch sensor 46 or may be a measurement value inputthrough operation of the electronic equipment 12 by the user.

When the model selection information 18 includes information relating tothe outer shape of the electronic equipment 12 as in the first example,the input-output model 70 that is different depending on whether thetouch surface of the electronic equipment 12 is flat or curved or bentmay be selected. This enables detection of a pen state suitable for thebending state of the touch sensor 46.

SECOND EXAMPLE

FIG. 10A is a schematic sectional view illustrating the state in which aprotective film 82 is stuck to the touch surface of the electronicequipment 12. In the example of the present diagram, the state in whichthe X line electrodes 47, the Y line electrode 48, the surface cover 80,and the protective film 82 are stacked from the lower side to the upperside is illustrated. The protective film 82 is an optional componentthat can be stuck by the user of the electronic equipment 12 as needed.As is understood from the present diagram, in the state in which the tipelectrode 60 of the electronic pen 14 is in contact with the touchsurface of the electronic equipment 12, the separation distance betweenthe tip electrode 60 and the X line electrode 47 (or the Y lineelectrode 48) changes depending on whether or not the protective film 82is present or the thickness thereof. Due to this, the magnitude ofcapacitance formed in association with capacitive coupling changes.

FIG. 10B is a diagram illustrating a change in signal distributionbetween before and after the sticking of the protective film 82. Theabscissa axis of the graph indicates the position (unit: mm) in theX-axis direction, and the ordinate axis of the graph indicates thesignal value (unit: none). As is understood from the present diagram,the signal distribution of “with protective film” has such a tendencythat the level of the signal value becomes lower across the boardcompared with the case of “without protective film.” Thus, inconsideration of such a difference in the distribution shape, multiplesets of the model parameters 20 corresponding to whether or not theprotective film 82 is disposed on the touch surface of the electronicequipment 12 or the thickness of the protective film 82 are prepared.

FIG. 11 is a diagram illustrating a second example of the data structureof the parameter DB 30 of FIG. 1. A second table of the parameter DB 30is data of a table format indicating the correspondence relation between“sensor type” indicating the type of the touch sensor 46, “equipmenttype” indicating the type of the electronic equipment 12, “film state”indicating the covering state of the protective film 82, and the“parameter set name” indicating the set name of the model parameters 20.The “sensor type” is classified according to the product name, modelnumber, production lot, manufacturer, or the like of the touch sensor46, for example. The “equipment type” is classified according to theproduct name, model number, production lot, manufacturer, or the like ofthe electronic equipment 12, for example. The “film state” is classifiedaccording to the presence or absence, thickness, product name, or thelike of the protective film 82, for example. Specifically, the “filmstate” may be qualitatively classified as “absent,” “present,” “thin,”“thick,” and so forth, or may be quantitatively classified according tothe measurement value of the thickness (unit: μm) or the like.

In this case, the information acquiring section 50 of the electronicequipment 12 acquires each of the sensor type, the equipment type, andthe film state as the model selection information 18 (step S2 in FIG.3). The sensor type may be type information stored in an electroniccomponent that configures the electronic equipment 12 (for example,touch IC 36) or may be type information input through operation of theelectronic equipment 12 by the user. The equipment type may be typeinformation stored in the memory 42 of the electronic equipment 12.Further, the film state may be state information input through operationof the electronic equipment 12 by the user.

When the model selection information 18 includes information relating tothe outer shape of the electronic equipment 12 as in the second example,the input-output model 70 that is different depending on whether or notthe protective film 82 is disposed on the touch surface of theelectronic equipment 12 or the thickness of the protective film 82 maybe selected. This enables detection of a pen state suited for thecovering state of the protective film 82.

THIRD EXAMPLE

FIG. 12A is a schematic side view illustrating the state in which thetip electrode 60 of the electronic pen 14 is worn out. The user carriesout writing operation while bringing the end part of the electronic pen14 into contact with the touch surface of the electronic equipment 12.Then, from the tip electrode 60 in the initial state, a worn-out part 90is removed due to wear, so that the tip electrode 60 is deformed into aremaining part 92 having a dull tip shape. That is, the geometricrelation between the tip electrode 60 and the sensor electrode (forexample, the X line electrode 47) changes, and signal distribution isdeformed correspondingly.

FIG. 12B is a diagram illustrating a change in signal distributionbetween before and after the wear of the tip electrode 60. The abscissaaxis of the graph indicates the position (unit: mm) in the X-axisdirection and the ordinate axis of the graph indicates the signal value(unit: none). As is understood from the present diagram, the signaldistribution of “worn state” has such a tendency that the width becomeswider and the peak becomes lower compared with the case of “initialstate.” Hence, in consideration of such a difference in the distributionshape, multiple sets of the model parameters 20 corresponding to whetheror not the tip electrode 60 is worn or the degree of the wear areprepared.

FIG. 13 is a diagram illustrating a third example of the data structureof the parameter DB 30 of FIG. 1. A third table of the parameter DB 30is data of a table format indicating the correspondence relation betweenthe “pen type” indicating the type of the electronic pen 14, “pen tipwear degree” indicating whether or not the tip electrode 60 is worn orthe degree thereof, and the “parameter set name” indicating the set nameof the model parameters 20. The “pen type” is classified according tothe product name, model number, production lot, manufacturer, or thelike of the electronic pen 14, for example. The “pen tip wear degree”may be qualitatively classified as “absent,” “present,” “low,” “high,”and so forth, or may be quantitatively classified according to thelength of the worn part 90, the length or curvature of the remainingpart 92, or the like.

In this case, the information acquiring section 50 of the electronicequipment 12 acquires each of the pen type and the pen tip wear degreeas the model selection information 18 (step S2 in FIG. 3). The pen typemay be type information included in a downlink signal from theelectronic pen 14 or may be type information input through operation ofthe electronic equipment 12 by the user. The pen tip wear degree may bea measurement value obtained through an image of the tip electrode 60captured by a camera or analysis processing of the image, or may be ameasurement value input through operation of the electronic equipment 12by the user.

When the model selection information 18 includes information relating tothe outer shape of the electronic pen 14 as in the third example, theinput-output model 70 that is different depending on whether or not thetip electrode 60 is worn or the degree of the wear may be selected. Thisenables detection of a pen state suitable for the wear state of the tipelectrode 60.

FOURTH EXAMPLE

Even in the ideal state without any change in the outer shape of theelectronic pen 14 or the electronic equipment 12, the appearancetendency of signal distribution differs depending on the combination ofthe electronic pen 14 and the touch sensor 46 in some cases. In view ofsuch a difference in the distribution shape, multiple sets of the modelparameters 20 corresponding to different combinations of the types ofthe electronic pen 14 and the touch sensor 46 may be prepared.

FIG. 14 is a diagram illustrating a fourth example of the data structureof the parameter DB 30 of FIG. 1. A fourth table of the parameter DB 30is data of a table format indicating the correspondence relation betweenthe “pen type” indicating the type of the electronic pen 14, the “sensortype” indicating the type of the touch sensor 46, and the “parameter setname” indicating the set name of the model parameters 20. Specificexamples of the pen type and the sensor type are similar to those of thecases of the above-described first to third examples, and hence,detailed description thereof is omitted.

When the model selection information 18 includes the type of theelectronic pen 14 and the type of the touch sensor 46 as in the fourthexample, the input-output model 70 that is different depending on thecombination of the electronic pen type and the touch sensor type may beselected. This enables detection of a pen state suitable for thecombination of the electronic pen 14 and the touch sensor 46.

FIFTH EXAMPLE

For example, even with the same electronic pen 14, the appearancetendency of signal distribution may differ depending on how the userholds the electronic pen 14 in some cases. In view of such a differencein the distribution shape, multiple sets of the model parameters 20corresponding to the combinations of the user and equipment (forexample, the electronic pen 14) may be prepared.

FIG. 15 is a diagram illustrating a fifth example of the data structureof the parameter DB 30 of FIG. 1. A fifth table of the parameter DB 30is data of a table format indicating the correspondence relation between“user ID” indicating identification information of the user, the “pentype” indicating the type of the electronic pen 14, and the “parameterset name” indicating the set name of the model parameters 20. The “userID” is identification information singularly managed by the serverdevice 16. The “pen type” is classified according to the product name,model number, production lot, manufacturer, or the like of theelectronic pen 14 as in the first example.

In this case, the information acquiring section 50 of the electronicequipment 12 acquires each of the user ID and the pen type as the modelselection information 18 (step S2 in FIG. 3). The user ID may be accountinformation of a generation application of the digital ink 58, or may bea host name given to the electronic equipment 12. The pen type may betype information included in a downlink signal from the electronic pen14 or may be type information input through operation of the electronicequipment 12 by the user.

When the model selection information 18 includes the type of any one ofthe electronic pen 14, the electronic equipment 12, and the touch sensor46 as in the fifth example, the input-output model 70 that is differentdepending on the combination of this type and the user may be selected.This enables detection of a pen state suited for the tendency of how theuser uses (e.g., holds) various kinds of equipment.

SIXTH EXAMPLE

Although the combinations including the type of the electronic pen 14have been described in the fourth and fifth examples, the combination isnot limited thereto, and various configurations may be considered.Specifically, a combination of two or more of various types including atype of the electronic pen 14, a type of the electronic equipment 12, atype of the touch sensor 46, and the user may be employed.Alternatively, a combination may be employed which further includes achange in terms of the outer shape of the electronic pen 14 or theelectronic equipment 12 in the above-described first to third examples.

Effects of Embodiments

As described above, the touch IC 36 as the pen state detection circuitis incorporated in the electronic equipment 12 having the touch sensor46 of the capacitive system made of planarly disposed multiple sensorelectrodes. The touch IC 36 acquires, from the touch sensor 46, signaldistribution indicating a change in the capacitance associated withapproach of the pen-side electrode of the electronic pen 14 (tipelectrode 60, upper electrode 62), and estimates the state of theelectronic pen 14 according to the input-output model 70. In theinput-output model 70 features relating to this signal distribution areinput and the state quantity of the electronic pen 14 is output. Thetouch IC 36 is configured to be capable of setting the input-outputmodel 70 that is different depending on the change in terms of the outershape of the electronic pen 14 or the electronic equipment 12.

Moreover, the electronic equipment 12 as the pen state detection deviceincludes, besides the above-described touch IC 36, the informationacquiring section 50 that acquires the model selection information 18relating to the outer shape of the electronic pen 14 or the electronicequipment 12 and the parameter setting section 52 that sets, in thetouch IC 36, the model parameters 20 that allow identification of theinput-output model 70 corresponding to the acquired model selectioninformation 18.

Further, the server device 16 as the parameter supply device isconfigured to be capable of mutually communicating with theabove-described electronic equipment 12. The server device 16 includesthe server-side storage section 26 that stores the model parameters 20in such a manner as to associate the model parameters 20 with the modelselection information 18, and the server-side control section 24 that,when receiving the model selection information 18 from the electronicequipment 12, carries out control of reading out the model parameters 20corresponding to the model selection information 18 from the server-sidestorage section 26 and transmitting the model parameters 20 to theelectronic equipment 12. In particular, when the electronic equipment 12is capable of bidirectionally communicating with the server device 16,the parameter setting section 52 of the electronic equipment 12 mayacquire the model parameters 20 corresponding to the model selectioninformation 18 from the server device 16 and set the model parameters20.

The configuration described above makes it possible to selectively setthe input-output model 70 suitable for the use condition of theelectronic pen 14 or the electronic equipment 12 (particularly, changein terms of the outer shape thereof) and to maintain the pen statedetection accuracy.

Further, the touch IC 36 acquires, from the touch sensor 46, signaldistribution indicating a change in the capacitance associated withapproach of the pen-side electrode included in the electronic pen 14,and estimates the state of the electronic pen 14 according to theinput-output model 70 in which features relating to the acquired signaldistribution are input and the state quantity of the electronic pen 14is output. The touch IC 36 is configured to be capable of setting theinput-output model 70 that is different depending on a combination oftwo or more of a type of the electronic pen 14, a type of the electronicequipment 12, a type of the touch sensor 46, and the user.

Further, the electronic equipment 12 includes, besides theabove-described touch IC 36, the information acquiring section 50 thatacquires the model selection information 18 relating to the combinationof two or more of such elements as a type of the electronic pen 14, atype of the electronic equipment 12, a type of the touch sensor 46, andthe user, and the parameter setting section 52 that sets, in the touchIC 36, the model parameters 20 that allow identification of theinput-output model 70 corresponding to the acquired model selectioninformation 18. Further, the server device 16 includes the server-sidestorage section 26 that stores the model parameters 20 in associationwith the model selection information 18, and the server-side controlsection 24 that, when receiving the model selection information 18 fromthe electronic equipment 12, carries out control of reading out themodel parameters 20 corresponding to the model selection information 18from the server-side storage section 26 and transmitting the modelparameters 20 to the electronic equipment 12.

The configuration described above makes it possible to selectively setthe input-output model 70 suitable for the use condition of theelectronic pen 14 and the electronic equipment 12 (in combination, inparticular) by the user and to maintain the pen state detectionaccuracy.

Furthermore, the electronic equipment 12 may be configured to be capableof setting the input-output model 70 in such a manner that detection ofthe electronic pen 14 serves as a trigger for carrying out the setting.Accordingly, a suitable input-output model 70 can be set when theelectronic pen 14 is in actual use.

MODIFICATION EXAMPLES

It is obvious that the present disclosure is not limited to theabove-described embodiments and can freely be changed without departingfrom the principles disclosed therein. Alternatively, the respectiveconfigurations may freely be combined to the extent no technicalcontradiction occurs.

First Modification Example

FIG. 16 is an overall configuration diagram of an input system 100 in afirst modification example. The input system 100 includes at least oneunit of electronic equipment 102, at least one electronic pen 104, andthe server device 16 having a configuration similar to that of the caseof FIG. 1.

Basically, the electronic equipment 102 has a configuration similar tothat of the electronic equipment 12 illustrated in FIG. 2. However, thecase is assumed in which the function of the communication module 38 isset to be stopped and the electronic equipment 102 is used offline.

The electronic pen 104 has a wireless communication function to carryout wireless communication with an external device by using a wirelesscommunication technology different from that used in the pen-sideelectrode, for example, Bluetooth (registered trademark), WiFi, 5thgeneration mobile communication system (what is generally called 5G), orthe like. This allows each electronic pen 104 to connect to the networkNT through a relay device 106.

The above-described input system 100 can carry out similar operationalong the sequence illustrated in FIG. 3. For example, in step S3, theelectronic equipment 102 transmits, to the electronic pen 104, an uplinksignal including the model selection information 18 acquired in step S2and identification information of the electronic equipment 102 (i.e.,equipment ID). Then, the electronic pen 104 transmits, to the serverdevice 16, data including the acquired model selection information 18and the acquired equipment ID, in the state in which the data isassociated with identification information of the electronic pen 104(i.e., pen ID). In this manner, the model selection information 18 issupplied to the server device 16.

Moreover, in step S6, the server device 16 transmits data including themodel parameters 20 selected in step S5 and the equipment ID to theelectronic pen 104 having the pen ID associated with the relevant modelselection information 18. Then, the electronic pen 104 transmits adownlink signal including the acquired model parameters 20 and theacquired equipment ID to the electronic equipment 102. In this manner,the model parameters 20 are supplied to the electronic equipment 102.

When the electronic equipment 102 and the server device 16 are capableof bidirectionally communicating via the relay by the electronic pen 104as described above, the parameter setting section 52 of the electronicequipment 102 may acquire the model parameters 20 corresponding to themodel selection information 18 from the electronic pen 104 and set themodel parameters 20. As a result, even when communication cannot bedirectly carried out between the electronic equipment 102 and the serverdevice 16, selection and setting of the model parameters 20 suitable forthe use condition of the electronic pen 104 or the electronic equipment102 can be carried out.

Second Modification Example

FIG. 17 is a block diagram illustrating one example of the configurationof electronic equipment 110 in a second modification example.Specifically, the electronic equipment 110 includes the touch paneldisplay 32, the display drive IC 34, the touch IC 36, the communicationmodule 38, a host processor 112, and a memory 114.

The host processor 112 is different from the configuration illustratedin FIG. 2 in that the host processor 112 further includes the modelselecting section 28. Moreover, the memory 114 is different from theconfiguration illustrated in FIG. 2 in that the memory 114 storesmultiple sets of the model parameters 20. By incorporating part offunctions of the server device 16 (FIG. 1) into the electronic equipment110 as described above, similar operation can be carried out along thesequence illustrated in FIG. 3 without the server device 16 beingprovided.

Specifically, steps S3, S4, S5, S6, and S7 relating to transmission andreception of data in the sequence of FIG. 3 can be omitted. In thiscase, in step S5, it suffices that the host processor 112 of theelectronic equipment 110 (more specifically, the model selecting section28) uses the model selection information 18 acquired in step S2, as asearch key, and selects, from among the multiple sets of the modelparameters 20 stored in the memory 114, the model parameters 20 thatallow identification of the input-output model 70 corresponding to themodel selection information 18.

When the memory 114 of the electronic equipment 110 can store multiplesets of the model parameters 20 as described above, the parametersetting section 52 may select, from among the multiple sets of the modelparameters 20 stored in the memory 114, the model parameters 20corresponding to the model selection information 18, and set the modelparameters 20. As a result, selection and setting of the modelparameters 20 suitable for the use condition of the electronic pen 14 orthe electronic equipment 110 can be carried out without the serverdevice 16 being provided.

Other Modification Examples

In the above-described embodiment, setting of the input-output model 70is triggered by detection of the electronic pen 14. However, the timingof the setting is not limited thereto. For example, the touch IC 36 maybe configured to be capable of dynamically setting the input-outputmodel 70 in such a manner that detection of a change in terms of theouter shape of the electronic pen 14 or the electronic equipment 12 isused as a trigger for the setting. Alternatively, the touch IC 36 mayalso be configured to be capable of dynamically setting the input-outputmodel 70 in such a manner that detection of a change in the combinationof two or more of a type of the electronic pen 14, a type of theelectronic equipment 12, a type of the touch sensor 46, and the user, isused as a trigger for the dynamic setting.

In the above-described embodiments, the input-output model 70 isconstructed by using the neural network illustrated in FIG. 7. However,the method of the machine learning is not limited thereto. For example,various methods including a logistic regression model, a support vectormachine (SVM), a decision tree, a random forest, and a boosting methodmay be employed. Alternatively, the data definition of the modelparameters 20 may be, in addition to the learning parameters, variouscoefficients to identify a function, a state quantity or a tableindicating a correction amount of the state quantity, or the like.

1. A pen state detection circuit incorporated in electronic equipment,the electronic equipment having a touch sensor of a capacitive systemmade of planarly disposed multiple sensor electrodes, the pen statedetection circuit configured to perform: acquiring, from the touchsensor, signal distribution indicating a change in capacitanceassociated with approach of a pen-side electrode included in anelectronic pen, and estimating a state of the electronic pen accordingto an input-output model in which features relating to the acquiredsignal distribution are input and a state quantity of the electronic penis output, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending ona change in an outer shape of the electronic pen or the electronicequipment.
 2. The pen state detection circuit according to claim 1,wherein the change in the outer shape is a dynamic change in anelectrical or magnetic coupling state of an interface between theelectronic pen and the electronic equipment that changes depending ontime despite that the electronic pen and the electronic equipment arestatically in a state indicated by the same information.
 3. The penstate detection circuit according to claim 1, wherein the pen statedetection circuit is configured to be capable of setting an input-outputmodel that is different depending on whether a touch surface of theelectronic equipment is flat or curved or bent.
 4. The pen statedetection circuit according to claim 1, wherein the pen state detectioncircuit is configured to be capable of setting an input-output modelthat is different depending on whether or not a protective film isdisposed on a touch surface of the electronic equipment or thickness ofthe protective film.
 5. The pen state detection circuit according toclaim 1, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending onwhether or not the pen-side electrode is worn out or a degree of thewear.
 6. The pen state detection circuit according to claim 1, whereinthe pen state detection circuit is configured to be capable of settingthe input-output model in such a manner that detection of the electronicpen is used as a trigger for the setting.
 7. A pen state detectionmethod carried out with use of a pen state detection circuitincorporated in electronic equipment, the electronic equipment having atouch sensor of a capacitive system made of planarly disposed multiplesensor electrodes, the pen state detection method comprising: acquiring,from the touch sensor, signal distribution indicating a change incapacitance associated with approach of a pen-side electrode included inan electronic pen; and estimating a state of the electronic penaccording to an input-output model in which features relating to theacquired signal distribution are input and a state quantity of theelectronic pen is output, wherein an input-output model that isdifferent depending on a change in an outer shape of the electronic penor the electronic equipment is set.
 8. A pen state detection devicecomprising: a pen state detection circuit incorporated in electronicequipment, the electronic equipment having a touch sensor of acapacitive system made of planarly disposed multiple sensor electrodes,the pen state detection circuit configured to perform acquiring, fromthe touch sensor, signal distribution indicating a change in capacitanceassociated with approach of a pen-side electrode included in anelectronic pen, and estimating a state of the electronic pen accordingto an input-output model in which features relating to the acquiredsignal distribution are input and a state quantity of the electronic penis output, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending ona change in an outer shape of the electronic pen or the electronicequipment; an information acquiring section configured to acquire modelselection information relating to the outer shape of the electronic penor the electronic equipment; and a parameter setting section configuredto set, in the pen state detection circuit, model parameters that allowidentification of the input-output model corresponding to the modelselection information acquired by the information acquiring section. 9.A parameter supply device configured to be capable of mutuallycommunicating with a pen state detection device, the pen state detectiondevice including: a pen state detection circuit incorporated inelectronic equipment having a touch sensor of a capacitive system madeof planarly disposed multiple sensor electrodes, the pen state detectioncircuit configured to perform acquiring, from the touch sensor, signaldistribution indicating a change in capacitance associated with approachof a pen-side electrode included in an electronic pen, and estimating astate of the electronic pen according to an input-output model in whichfeatures relating to the acquired signal distribution are input and astate quantity of the electronic pen is output, wherein the pen statedetection circuit is configured to be capable of setting an input-outputmodel that is different depending on a change in an outer shape of theelectronic pen or the electronic equipment; an information acquiringsection configured to acquire model selection information relating tothe outer shape of the electronic pen or the electronic equipment; and aparameter setting section configured to set, in the pen state detectioncircuit, model parameters that allow identification of the input-outputmodel selected according to the model selection information acquired bythe information acquiring section; the parameter supply devicecomprising: a storage section configured to store the model parametersin association with the model selection information; and a controlsection that, when receiving the model selection information from thepen state detection device, carries out control of reading out the modelparameters corresponding to the model selection information from thestorage section and transmitting the model parameters to the pen statedetection device.
 10. A pen state detection circuit incorporated inelectronic equipment, the electronic equipment having a touch sensor ofa capacitive system made of planarly disposed multiple sensorelectrodes, the pen state detection circuit configured to perform:acquiring, from the touch sensor, signal distribution indicating achange in capacitance associated with approach of a pen-side electrodeincluded in an electronic pen; and estimating a state of the electronicpen according to an input-output model in which features relating to theacquired signal distribution are input and a state quantity of theelectronic pen is output, wherein the pen state detection circuit isconfigured to be capable of setting an input-output model that isdifferent depending on a combination of two or more of a type of theelectronic pen, a type of the electronic equipment, a type of the touchsensor, and a user.
 11. The pen state detection circuit according toclaim 10, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending ona combination of the type of the electronic pen and the type of thetouch sensor.
 12. The pen state detection circuit according to claim 10,wherein the pen state detection circuit is configured to be capable ofsetting an input-output model that is different depending on acombination of the type of any one of the electronic pen, the electronicequipment, and the touch sensor and the user.
 13. The pen statedetection circuit according to claim 10, wherein the pen state detectioncircuit is configured to be capable of setting the input-output model insuch a manner that detection of the electronic pen is used as a triggerfor the setting.
 14. A pen state detection method carried out with useof a pen state detection circuit incorporated in electronic equipment,the electronic equipment having a touch sensor of a capacitive systemmade of planarly disposed multiple sensor electrodes, the pen statedetection method comprising: acquiring, from the touch sensor, signaldistribution indicating a change in capacitance associated with approachof a pen-side electrode included in an electronic pen; and estimating astate of the electronic pen according to an input-output model in whichfeatures relating to the acquired signal distribution are input and astate quantity of the electronic pen is output, wherein an input-outputmodel that is set differently depending on a combination of two or moreof a type of the electronic pen, a type of the electronic equipment, atype of the touch sensor, and a user.
 15. A pen state detection devicecomprising: a pen state detection circuit incorporated in electronicequipment, the electronic equipment having a touch sensor of acapacitive system made of planarly disposed multiple sensor electrodes,the pen state detection circuit configured to perform acquiring, fromthe touch sensor, signal distribution indicating a change in capacitanceassociated with approach of a pen-side electrode included in anelectronic pen, and estimating a state of the electronic pen accordingto an input-output model in which features relating to the acquiredsignal distribution are input and a state quantity of the electronic penis output, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending ona combination of two or more of a type of the electronic pen, a type ofthe electronic equipment, a type of the touch sensor, and a user; aninformation acquiring section configured to acquire model selectioninformation relating to the combination of two or more of the type ofthe electronic pen, the type of the electronic equipment, the type ofthe touch sensor, and the user; and a parameter setting sectionconfigured to set, in the pen state detection circuit, model parametersthat allow identification of the input-output model corresponding to themodel selection information acquired by the information acquiringsection.
 16. A parameter supply device configured to be capable ofmutually communicating with a pen state detection device, the pen statedetection device including: a pen state detection circuit incorporatedin electronic equipment having a touch sensor of a capacitive systemmade of planarly disposed multiple sensor electrodes, the pen statedetection circuit configured to perform acquiring, from the touchsensor, signal distribution indicating a change in capacitanceassociated with approach of a pen-side electrode included in anelectronic pen, and estimating a state of the electronic pen accordingto an input-output model in which features relating to the acquiredsignal distribution are input and a state quantity of the electronic penis output, wherein the pen state detection circuit is configured to becapable of setting an input-output model that is different depending ona combination of two or more of a type of the electronic pen, a type ofthe electronic equipment, a type of the touch sensor, and a user, aninformation acquiring section configured to acquire model selectioninformation relating to the combination of two or more of the type ofthe electronic pen, the type of the electronic equipment, the type ofthe touch sensor, and the user, and a parameter setting sectionconfigured to set, in the pen state detection circuit, model parametersthat allow identification of the input-output model corresponding to themodel selection information acquired by the information acquiringsection, the parameter supply device comprising: a storage sectionconfigured to store the model parameters in association with the modelselection information; and a control section that, when receiving themodel selection information from the pen state detection device, carriesout control of reading out the model parameters corresponding to themodel selection information from the storage section and transmittingthe model parameters to the pen state detection device.
 17. The penstate detection device according to claim 15, wherein: the pen statedetection device is capable of bidirectionally communicating with aparameter supply device that stores the model parameters in associationwith the model selection information, and the parameter setting sectionis configured to acquire the model parameters corresponding to the modelselection information from the parameter supply device and to set themodel parameters.
 18. The pen state detection device according to claim15, wherein: the pen state detection device is capable ofbidirectionally communicating, via the electronic pen, with a parametersupply device that stores the model parameters in association with themodel selection information, and the parameter setting section isconfigured to acquire the model parameters corresponding to the modelselection information from the electronic pen and to set the modelparameters.
 19. The pen state detection device according to claim 15,further comprising: a memory that stores multiple sets of modelparameters, wherein: the parameter setting section is configured toselect the model parameters corresponding to the model selectioninformation from among the multiple sets of the model parameters storedin the memory, and to set the model parameters.